KR102586312B1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display device - Google Patents

Abstract

식 중 P₁, P₂ 는 페닐 또는 비페닐기이고 방향 고리 상의 수소는 메틸기 또는 불소기로 치환되어 있어도 된다. 또 Q 는 2 가의 유기기이고, n1, n2 는 0 내지 5 의 정수이다. 단, n1, n2 중 적어도 하나가 0 인 경우 Q 는 산소 원자이다.It is a liquid crystal aligning agent containing polyimide, which is a reaction product of a tetracarboxylic acid dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic dianhydride, and a diamine component, and a diamine component. This liquid crystal aligning agent contains at least 1 type chosen from the diamine of the following formula [A], and the imidation rate of a polyimide is 70% or more.

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Moreover, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, if at least one of n1 and n2 is 0, Q is an oxygen atom.

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display device

The present invention relates to liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal display elements.

A liquid crystal display element is constructed by sandwiching a liquid crystal layer with a pair of transparent substrates provided with electrodes. And in a liquid crystal display element, an organic film made of an organic material is used as a liquid crystal alignment film so that the liquid crystal is in a desired state of alignment between substrates. That is, the liquid crystal alignment film is a structural member of the liquid crystal display element, and is formed on the surface in contact with the liquid crystal of the substrate holding the liquid crystal, and plays the role of aligning the liquid crystal in a certain direction between the substrates. Furthermore, the pretilt angle of the liquid crystal can be controlled by the liquid crystal alignment film. There are known methods for lowering the pretilt angle, mainly by selecting the polyimide structure (see Patent Documents 1 and 2).

Japanese Patent Publication No. 9-188761 Japanese Patent Publication No. 10-123532

Meanwhile, with recent improvements in the performance of liquid crystal display elements, in addition to applications such as large-screen, high-definition liquid crystal televisions, liquid crystal displays for automotive applications, such as car navigation systems, meter panels, surveillance cameras, and medical camera monitors, etc. devices are being used, and due to the demand for viewing angle characteristics, a lower pretilt angle is required for rubbing alignment films than before.

In addition, viewing angle dependence of color taste resulting from the pretilt angle, so-called color shift, has been pointed out as a problem, and in order to solve this problem, an alignment film having a pretilt angle of 1 degree or less is specifically required.

As a result of repeated studies to achieve the above-described object, the inventors found that a liquid crystal aligning agent having the following structure was optimal for achieving the above-mentioned object, and completed the present invention.

In this way, the present invention is based on the above findings and has the following gist.

1. A liquid crystal aligning agent containing polyimide, which is a reaction product of a carboxylic acid dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic dianhydride, and a diamine component, and diamine A liquid crystal aligning agent in which a component contains at least 1 type chosen from the diamine (hereinafter also referred to as specific diamine) of the following formula [A], and the imidation rate of a polyimide is 70% or more.

[Formula 1]

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Moreover, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, if at least one of n1 and n2 is 0, Q is an oxygen atom.

Preferred specific examples of [A] include diamines of the following formulas [A-1] to [A-6].

[Formula 2]

By using the liquid crystal aligning agent of the present invention, a liquid crystal aligning film that satisfies the various characteristics required for the liquid crystal aligning film and provides a low pretilt angle of 1 degree or less can be obtained.

<Aliphatic, alicyclic tetracarboxylic acid derivatives>

The polyimide contained in the liquid crystal aligning agent of the present invention contains a tetracarboxylic dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and a specific diamine. It is obtained by imidizing a polyimide precursor obtained from a diamine component (hereinafter also referred to as a specific polymer). Below, specific examples of materials used and manufacturing methods are described in detail.

Tetracarboxylic acid derivatives used in the production of polyimide precursors include not only tetracarboxylic dianhydride, but also its derivatives, tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester, and tetracarboxylic acid. Examples include boxylic acid dialkyl ester dihalides.

As aliphatic and alicyclic tetracarboxylic dianhydrides or their derivatives, those represented by the following formula (4) are particularly preferable.

[Formula 3]

In formula (4), preferred structures of X ₁ include the following formulas (X1-1) to (X1-24).

[Formula 4]

[Formula 5]

[Formula 6]

In formulas (X1-1) to (X1-4), R ₃ to R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, or a C 2 to It is an alkynyl group of 6, a monovalent organic group of 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. From the viewpoint of liquid crystal orientation, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and are preferably a hydrogen atom or a methyl group.

Specific examples of formula (X1-1) include the following formulas (X1-1-1) to (X1-1-6). In terms of liquid crystal orientation and sensitivity to light reaction, (X1-1-1) is particularly preferable.

[Formula 7]

<Specific diamine>

The diamine component used for manufacture of the polyimide contained in the liquid crystal aligning agent of this invention contains at least 1 type chosen from the diamine of the following formula [A].

[Formula 8]

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Moreover, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, if at least one of n1 and n2 is 0, Q is an oxygen atom.

Here, when (n1 + n2) ≥ 1 and either n1 or n2 is 0, Q is preferably an oxygen atom, and the formula [A] in this case is expressed as [A'] below.

[Formula 9]

In the formula, X is a divalent organic group selected from the structures below.

[Formula 10]

* represents a bond with an oxygen atom, respectively.

Preferred specific examples of [A] include diamines of the following formulas [A-1] to [A-6]. These may be used alone or in combination.

[Formula 11]

The preferable content of the diamine of the formula [A] is preferably 40% to 80% of the total diamine components, more preferably 40% to 70%, and still more preferably 40% to 60%.

<Other diamines>

In addition to the diamine of the said formula [A], the diamine component used for manufacture of the polyimide contained in the liquid crystal aligning agent of this invention can use various diamine according to the characteristic of the liquid crystal aligning agent requested|required.

Other diamines are represented by the following formula (5).

[Formula 12]

In the formula (5), A ₁ and A ₂ are each independently a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, or an alkynyl group with 2 to 5 carbon atoms.

The structure of Y ₁ is not particularly limited. Preferred structures include (Y-1) to (Y-177) below.

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

[Formula 24]

[Formula 25]

[Formula 26]

[Formula 27]

[Formula 28]

[Formula 29]

[Formula 30]

[Formula 31]

In the above formula, Me represents a methyl group, and R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[Formula 32]

From the viewpoint of improving the solubility of the polymer, it is preferable that the structure represented by the following formula (6) is included in the structure of any Y ₁ .

[Formula 33]

In the above formula (6), D is a thermally desorbable group that desorbs preferably at 150 to 230°C, more preferably at 180 to 230°C and is replaced by a hydrogen atom. Specific examples of Y containing the structure represented by the above formula (6) include (Y-124), (Y-158) to (Y-163).

<Polyamic acid>

The polyamic acid, which is a polyimide precursor used in the present invention, contains a tetracarboxylic dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride and a specific diamine. It is a polyimide precursor obtained from a diamine component, and can be manufactured by the method shown below.

Specifically, a tetracarboxylic dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride and a diamine component containing a specific diamine are mixed in the presence of an organic solvent. , -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 12 hours.

The organic solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of monomers and polymers, and one or two types of these are used. You may use a mixture of the above. The polymer concentration is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoints of polymer precipitation less likely to occur and a high molecular weight body being easy to obtain.

The polyamic acid obtained as described above can be recovered by injecting the reaction solution into a poor solvent while stirring well to precipitate the polymer. Additionally, purified polyamic acid powder can be obtained by performing precipitation several times, washing with a poor solvent, and drying at room temperature or by heating. The poor solvent is not particularly limited, but examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Polyamic acid ester>

Polyamic acid ester, which is one of the polyimide precursors used in the present invention, can be manufactured by the method of (I), (II), or (III) shown below.

(I) When manufactured with polyamic acid

Polyamic acid ester can be synthesized by esterifying polyamic acid obtained from tetracarboxylic dianhydride and diamine. Specifically, it is synthesized by reacting polyamic acid and an esterifying agent in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 4 hours. You can.

The esterifying agent is preferably one that can be easily removed by purification, and includes N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentylbutyl acetal, N,N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene , 1-propyl-3-p-tolyltriazene, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, etc. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents per 1 mole of repeating units of the polyamic acid.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone due to the solubility of the polymer, and these are used singly or in a mixture of two or more. You can use it. The concentration of the polymer in the reaction liquid is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoints of polymer precipitation less likely to occur and a high molecular weight body being easy to obtain.

(II) When manufactured by reaction of tetracarboxylic acid diester dichloride and diamine

Polyamic acid ester can be manufactured from tetracarboxylic acid diester dichloride and diamine. Specifically, tetracarboxylic acid diester dichloride and diamine are reacted in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 20°C. It can be synthesized by reacting for 4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used as the base, but pyridine is preferred so that the reaction proceeds gently. The amount of base used is preferably 2 to 4 times the mole of tetracarboxylic acid diester dichloride from the viewpoint of being an amount that is easy to remove and making it easy to obtain a high molecular weight body.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of monomers and polymers, and these may be used one type or in a mixture of two or more types. The polymer concentration in the reaction liquid is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoints of polymer precipitation less likely to occur and a high molecular weight body being easy to obtain. In addition, in order to prevent hydrolysis of tetracarboxylic acid diester dichloride, the solvent used in the synthesis of polyamic acid ester is preferably dehydrated as much as possible, and it is desirable to prevent mixing of external air in a nitrogen atmosphere. .

(III) When manufactured by reaction of tetracarboxylic acid diester and diamine

Polyamic acid ester can be manufactured by polycondensing tetracarboxylic acid diester and diamine. Specifically, tetracarboxylic acid diester and diamine are reacted in the presence of a condensing agent, a base, and an organic solvent at 0°C to 150°C, preferably 0°C to 100°C, for 30 minutes to 24 hours, preferably 3. It can be prepared by reacting for ~15 hours.

The condensing agent includes triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, and dimethoxy-1. ,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazole- 1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphite, (2,3-dihydro-2-thioxo-3-benzooxazolyl)phosphonate diphenyl, etc. You can use it. The amount of condensing agent added is preferably 2 to 3 times the mole of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of base used is preferably 2 to 4 times the mole of the diamine component from the viewpoint of being an amount that is easy to remove and making it easy to obtain a high molecular weight body.

Additionally, in the above reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The amount of Lewis acid added is preferably 0 to 1.0 times the mole of the diamine component.

Among the three methods for producing polyamic acid ester, the production method (I) or (II) is particularly preferable because a high molecular weight polyamic acid ester is obtained.

The solution of polyamic acid ester obtained as described above can be injected into a poor solvent while stirring well to precipitate the polymer. Precipitation can be performed several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polyamic acid ester powder. The poor solvent is not particularly limited, but examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Polyimide>

The polyimide used in the present invention can be manufactured by imidizing the polyamic acid or polyamic acid ester. The imidation rate of the polyimide used in this invention is preferably 70 to 99% from the viewpoint of electrical properties. When producing polyimide from polyamic acid ester, chemical imidization is simple by adding a basic catalyst to the polyamic acid ester solution or the polyamic acid solution obtained by dissolving polyamic acid ester resin powder in an organic solvent. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization process.

Chemical imidization can be performed by stirring the polyamic acid or polyamic acid ester to be imidized in the presence of a basic catalyst and an acid anhydride in an organic solvent. As the organic solvent, the solvent used during the polymerization reaction described above can be used. Basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity to proceed with the reaction. Additionally, acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among these, acetic anhydride is preferred because it facilitates purification after completion of the reaction.

The temperature when performing the imidization reaction is, for example, -20°C to 120°C, preferably 0°C to 100°C, and the reaction time can be from 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mole times the amic acid group, preferably 2 to 20 mole times, and the amount of the acid anhydride is 1 to 50 mole times the amic acid group, preferably 3 to 30 mole times. The imidization rate of the obtained polymer can be controlled by adjusting the catalyst amount, temperature, and reaction time.

Since the added catalyst, etc. remain in the solution after the imidization reaction of polyamic acid ester or polyamic acid, the obtained imidized polymer is recovered by the means described below and re-dissolved in an organic solvent to form the liquid crystal of the present invention. It is preferable to use it as an orientation agent.

The solution of polyimide obtained as described above can be injected into a poor solvent while stirring well to precipitate the polymer. Precipitation can be performed several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polyamic acid ester powder.

The poor solvent is not particularly limited, but includes methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid crystal alignment agent>

The liquid crystal aligning agent of the present invention has the form of a solution in which a polymer containing a specific polymer is dissolved in an organic solvent. The molecular weight of the polyimide precursor and polyimide described in the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and even more preferably 10,000 to 100,000 in weight average molecular weight. Moreover, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

In the liquid crystal aligning agent, 2-10 mass % is preferable and, as for content of the specific polymer in the liquid crystal aligning agent of this invention, 3-8 mass % is more preferable.

In addition to the specific polymer, the liquid crystal aligning agent of the present invention may contain a polyamic acid that is a reaction product of an arbitrary tetracarboxylic acid derivative component and an arbitrary diamine component.

Moreover, when a liquid crystal aligning agent contains the said polyamic acid, 10-900 mass parts is preferable with respect to 100 mass parts of polyimides, and, as for the ratio, 25-700 mass parts is more preferable.

As for all the polymer components in the liquid crystal aligning agent of this invention, other polymers may be mixed. Other polymers include cellulose polymer, acrylic polymer, methacrylic polymer, polystyrene, polyamide, and polysiloxane. The content of other polymers is preferably 0.5 to 15 parts by mass, and more preferably 1 to 10 parts by mass, relative to a total of 100 parts by mass of polyimide or polyamic acid.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed depending on the thickness setting of the coating film to be formed, but is preferably 1% by weight or more in terms of forming a uniform and defect-free coating film, and the solution In terms of storage stability, 10% by weight or less is preferable.

The solvent in the liquid crystal aligning agent of the present invention is a solvent (also referred to as a good solvent) that dissolves the polyimide precursor and polyimide, and the coating properties and surface smoothness of the liquid crystal aligning film when the liquid crystal aligning agent is applied. An improving solvent (also called a poor solvent) is preferably used. Below, specific examples of other solvents are given, but are not limited to these examples.

Specific examples of good solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, 1,3-dimethylimidazolidinone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N -Dimethylpropanamide or 4-hydroxy-4-methyl-2-pentanone can be mentioned.

Specific examples of poor solvents include 1-butoxy-2-propanol, 2-butoxy-1-propanol, 2-propoxyethanol, 2-(2-propoxyethoxy)ethanol, and 1-propoxy-2. -Propanolethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl Alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexane All, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2, 3-Butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol Dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3- Pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol Diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, butyl cellosolve, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, Diethylene glycol, propylene glycol, 1-(butoxyethoxy)propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene Glycol Monomethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monobutyl Ether Acetate, Ethylene Glycol Monoacetate, Ethylene Glycol Diacetate, Diethylene Glycol Monoethyl Ether Acetate, Propylene Glycol Diacetate, Diisopentyl Ether, Diethylene Glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate , ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropyl propionate, butyl 3-methoxypropionate, methyl lactate ester, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate ester, diisobutyl ketone. , ethylcarbitol, etc.

Moreover, as a poor solvent, a solvent represented by the following formula is also preferably used.

[Formula 34]

R ₂₄ and R ₂₅ are each independently a straight-chain or branched alkyl group having 1 to 8 carbon atoms. However, R ₂₄ + R ₂₅ is an integer greater than 3.

Moreover, as a poor solvent, when the solubility to the solvent of the polyimide precursor and polyimide contained in a liquid crystal aligning agent is high, the solvent shown by following [D-1] - formula [D-3] is preferable.

[Formula 35]

In formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, in formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-3], D ³ represents an alkyl group having 1 to 4 carbon atoms.

In addition, the liquid crystal aligning agent of the present invention has at least one substituent selected from the group consisting of a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group, or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group, and a lower alkoxyalkyl group. It may contain a crosslinkable compound having a crosslinkable compound or a crosslinkable compound having a polymerizable unsaturated bond.

As such a crosslinkable compound, various known compounds can be used depending on the purpose. Preferably used are the following compounds.

[Formula 36]

The content of the crosslinkable compound is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of all polymer components. Among these, in order for the crosslinking reaction to proceed and achieve the desired effect, 0.1 to 100 parts by mass is preferable, and 1 to 50 parts by mass is more preferable.

The liquid crystal aligning agent of the present invention can contain a compound that improves the uniformity and surface smoothness of the film thickness of the liquid crystal aligning film when the liquid crystal aligning agent is applied.

Compounds that improve the uniformity and surface smoothness of the film thickness of the liquid crystal alignment film include fluorine-based surfactants, silicone-based surfactants, and non-ionic surfactants.

The usage-amount of surfactant is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of all polymer components contained in the liquid crystal aligning agent.

Moreover, when baking a silane coupling agent for the purpose of improving the adhesiveness of a liquid crystal alignment film and a board|substrate, and a coating film, you may contain an imidization accelerator for the purpose of efficiently advancing imidization by heating a polyimide precursor, etc.

<Liquid crystal alignment film, liquid crystal display device>

The liquid crystal aligning film of this invention is a film|membrane obtained by apply|coating said liquid crystal aligning agent to a board|substrate, drying, and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate with high transparency, and plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, and polycarbonate substrates can also be used. In that case, it is preferable to use a substrate on which ITO electrodes for driving the liquid crystal are formed, in terms of simplification of the process. Additionally, in a reflective liquid crystal display device, an opaque material such as a silicon wafer can be used as long as it is a single-sided substrate, and a light-reflecting material such as aluminum can also be used for the electrode in this case.

Industrially, the application method of the liquid crystal aligning agent is generally performed by screen printing, offset printing, flexo printing, or inkjet method, and other application methods include the dip method, roll coater method, and slit coater method. , spinner method, spray method, etc. are known.

After the liquid crystal aligning agent is applied to the substrate, the solvent can be evaporated using a heating means such as a hot plate, a thermal circulation oven, or an IR (infrared) oven to form a liquid crystal alignment film. For the drying and baking steps after applying the liquid crystal aligning agent, arbitrary temperature and time can be selected. Usually, in order to sufficiently remove the solvent contained, the conditions include baking at 50 to 120°C for 1 to 10 minutes, and then baking at 150 to 300°C for 5 to 120 minutes. Since the reliability of a liquid crystal display element may fall when it is too thin, the thickness of the liquid crystal aligning film after baking is preferably 5 to 300 nm, and 10 to 200 nm is more preferable.

After applying and baking the liquid crystal aligning agent of this invention on a board|substrate, it can be aligned with a rubbing process, a photo-alignment process, etc., and can be used as a liquid crystal aligning film without an orientation process for vertical alignment purposes, etc. In alignment treatment such as rubbing treatment or photo-alignment treatment, already known methods and devices can be used.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element with a passive matrix structure will be described as an example. Additionally, a liquid crystal display device may have an active matrix structure in which a switching device such as a TFT (Thin Film Transistor) is formed in each pixel portion that constitutes an image display.

Specifically, a transparent glass substrate is prepared, a common electrode is formed on one substrate, and a segment electrode is formed on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned to enable desired image display. Next, an insulating film is formed on each substrate to cover the common electrode and the segment electrode. The insulating film can be, for example, a SiO ₂ -TiO ₂ film formed by a sol-gel method.

Next, a liquid crystal alignment film is formed on each substrate, the other substrate is overlapped with one substrate so that the liquid crystal alignment film surfaces face each other, and the periphery is adhered with a sealant. In order to control the substrate gap, the sealant is usually mixed with a spacer, and it is desirable to distribute the spacer for controlling the substrate gap even on the in-plane portion where the sealant is not formed. An opening through which liquid crystal can be filled from the outside is formed in a part of the sealant. Next, the liquid crystal material is injected into the space surrounded by the two substrates and the sealant through the opening formed in the sealant, and this opening is then sealed with an adhesive. For injection, a vacuum injection method may be used, or a method using capillary action in the air may be used. The liquid crystal material may be either a positive liquid crystal material or a negative liquid crystal material, but a negative liquid crystal material is preferable. Next, the polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surface of the two substrates opposite to the liquid crystal layer.

Example

Below, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to these Examples. In addition, the abbreviations for compounds and solvents are as follows.

NMP: N-methyl-2-pyrrolidone

GBL: γ-butyrolactone

BCS: Butylcellosolve

DA-1 to DA-12, CA-1 to CA-6: Compounds represented by the following structural formulas.

AD-1: 3-Glycidoxypropyltriethoxysilane

AD-2: A compound represented by the structural formula below.

[Formula 37]

[Formula 38]

<Viscosity>

In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample volume of 1.1 ml, a cone rotor TE-1 (1°34', R24), and a temperature of 25°C. did.

<Measurement of imidization rate of polyimide>

The imidization rate of the polyimide in the synthesis example was measured as follows. 30 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, ϕ5 (manufactured by Kusano Science Co., Ltd.)) and mixed with deuterated dimethyl sulfoxide (DMSO-d6, 0.05% by mass TMS (tetramethylsilane)). (0.53 ml) was added and ultrasonic waves were applied to completely dissolve it. Proton NMR of this solution was measured at 500 MHz using an NMR measuring device (JNW-ECA500) (manufactured by Nippon Electronics Datum Co., Ltd.). The imidization rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of amidic acid appearing around 9.5 ppm to 10.0 ppm. It was obtained by the following equation using the integrated value.

Imidation rate (%) = (1 - α·x/y) × 100

In the above formula, x is the proton peak integration value derived from the NH group of amidic acid, y is the peak integration value of the reference proton, and α is the NH of amidic acid in the case of polyamic acid (imidation rate 0%). It is the ratio of the number of standard protons to one basic proton.

(Synthesis Example 1)

In a 7 liter separable flask equipped with a stirring device and a nitrogen inlet tube, 225 g (3770 mmol) of DA-1, 167 g (419 mmol) of DA-2, and 117 g (210 mmol) of DA-3 were added. mol) It was weighed, 3130 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 204 g (910 mmol) of CA-1 was added, 616 g of NMP was further added, and it stirred at 40 degreeC under nitrogen atmosphere for 6 hours. Additionally, 79.0 g (402 mmol) of CA-2 was added, 709 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 270 mPa·s) PAA-B1. got it

In a 2 liter Erlenmeyer flask containing a stirrer, 400 g of this polyamic acid solution was added, 350 g of NMP, 32.4 g of acetic anhydride, and 8.39 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. The reaction was performed for 4 hours. This reaction solution was poured into 2770 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 87%).

Furthermore, 40.0 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 293 g of NMP was added, and the mixture was stirred at 70°C for 24 hours to dissolve, thereby obtaining polyimide solution SPI-A1.

(Synthesis Example 2)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.24 mmol) of DA-3. mol) It was weighed, 54.3 g of NMP was added, and it was dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, 15.5 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.26 g (11.5 mmol) of CA-2 was added, 6.80 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1300 mPa·s).

In a 100 ml Erlenmeyer flask containing a stirrer, 27.0 g of this polyamic acid solution was added, 18.0 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 86%).

Furthermore, 4.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and the mixture was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-A2.

(Synthesis Example 3)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.24 mmol) of DA-3. mol) was weighed, 50.9 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, 18.0 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Additionally, 2.63 g (11.7 mmol) of CA-1 was added, 9.70 g of NMP was further added, and the mixture was stirred at 40°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1180 mPa·s).

In a 100 ml Erlenmeyer flask containing a stirrer, 25.0 g of this polyamic acid solution was added, 8.33 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 86%).

Furthermore, 4.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-A3.

(Synthesis Example 4)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 4.82 g (16.4 mmol) of DA-1, 3.58 g (8.98 mmol) of DA-2, and 2.50 g (4.49 mmol) of DA-3. mol) was weighed and taken, 53.3 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 4.96 g (22.1 mmol) of CA-1 was added, 19.3 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Additionally, 1.50 g (5.99 mmol) of CA-4 was added, 6.35 g of NMP was further added, and the mixture was stirred at 40°C for 15 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 427 mPa·s).

In a 100 ml Erlenmeyer flask containing a stirrer, 30.0 g of this polyamic acid solution was added, 15.0 g of NMP, 2.85 g of acetic anhydride, and 0.737 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 84%).

Furthermore, 4.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and the mixture was stirred and dissolved at 70°C for 24 hours to obtain a polyimide solution SPI-A4.

(Synthesis Example 5)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 2.89 g (9.88 mmol) of DA-1, 3.94 g (9.89 mmol) of DA-2, and 2.75 g (4.94 mmol) of DA-3. mol), 2.01 g (8.22 mmol) of DA-4 was weighed, 49.5 g of NMP was added, and it was dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.25 g (21.4 mmol) of CA-3 was added, 14.7 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.04 g (10.4 mmol) of CA-2 was added, 6.96 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1170 mPa·s).

In a 100 ml Erlenmeyer flask containing a stirrer, 25.0 g of this polyamic acid solution was added, 16.6 g of NMP, 2.81 g of acetic anhydride, and 0.728 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 160 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 82%).

Furthermore, 4.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-A5.

(Synthesis Example 6)

In a 300 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 6.33 g (15.8 mmol) of DA-2, 4.42 g (7.94 mmol) of DA-3, and 8.52 g (29.1 mmol) of DA-8. mol) It was weighed and taken, 150 g of NMP was added, and it was dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 7.72 g (34.4 mmol) of CA-1 was added, 10.0 g of NMP was further added, and it stirred at 40 degreeC under nitrogen atmosphere for 6 hours. Furthermore, 3.38 g (17.2 mmol) of CA-2 was added, 10.0 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 190 mPa·s).

In a 500 ml Erlenmeyer flask containing a stirrer, 150 g of this polyamic acid solution was added, 130 g of NMP, 12.1 g of acetic anhydride, and 3.13 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. The reaction was performed for 4 hours. This reaction solution was poured into 1040 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 81%).

Furthermore, 4.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain a polyimide solution SPI-A6.

(Synthesis Example 7)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 1.12 g (4.49 mmol) of DA-5, 1.49 g (7.47 mmol) of DA-6, and 0.590 g (2.97 mmol) of DA-7. mol) was weighed, 15.5 g of NMP and 15.5 g of GBL were added, and the mixture was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 1.15 g (5.86 mmol) of CA-2 was added, 5.00 g of NMP and 5.00 g of GBL were further added, and the mixture was stirred at 25°C under nitrogen atmosphere for 1 hour. Additionally, 2.60 g (8.83 mmol) of CA-5 was added, 5.00 g of NMP and 5.00 g of GBL were added, and the mixture was stirred at 50°C for 12 hours under a nitrogen atmosphere to form a polyamic acid solution (viscosity: 200 mPa). ·s) PAA-A1 was obtained.

(Synthesis Example 8)

30.0 g of the polyamic acid solution PAA-B1 obtained in Synthesis Example 1 was aliquoted, 26.2 g of NMP, 2.44 g of acetic anhydride, and 0.630 g of pyridine were added, stirred at room temperature for 30 minutes, and then reacted at 40°C for 30 minutes. I ordered it. This reaction solution was poured into 150 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 40%).

Furthermore, 2.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 14.6 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-B1.

(Synthesis Example 9)

In a 200 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 8.04 g (27.5 mmol) of DA-1, 5.98 g (15.0 mmol) of DA-2, and 4.17 g (7.50 mmol) of DA-3. mol) was weighed, 111 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 7.29 g (32.5 mmol) of CA-1 was added, 22.0 g of NMP was further added, and it stirred at 40 degreeC under nitrogen atmosphere for 6 hours. Furthermore, 3.16 g (14.5 mmol) of CA-6 was added, 28.5 g of NMP was further added, and the mixture was stirred at 50°C in a nitrogen atmosphere for 12 hours to obtain a polyamic acid solution (viscosity: 280 mPa·s).

In a 300 ml Erlenmeyer flask containing a stirrer, 100 g of this polyamic acid solution was added, 87.5 g of NMP, 8.02 g of acetic anhydride, and 2.07 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. The reaction was performed for 4 hours. This reaction solution was poured into 700 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 82%).

Furthermore, 10.0 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 73.3 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-B2.

(Synthesis Example 10)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 5.62 g (19.3 mmol) of DA-8, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 mmol) of DA-3. mol) It was weighed, 54.3 g of NMP was added, and it was dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, 15.5 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.29 g (11.7 mmol) of CA-2 was added, 8.30 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1210 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain a polyimide powder (imidation rate: 83%), which was further dissolved in NMP to obtain a polyimide solution SPI-A7. got it

(Synthesis Example 11)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 5.62 g (19.3 mmol) of DA-9, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 mmol) of DA-3. mol) It was weighed, 54.3 g of NMP was added, and it was dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, 15.5 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.33 g (11.9 mmol) of CA-2 was added, 8.50 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 900 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain a polyimide powder (imidation rate: 80%), which was further dissolved in NMP to obtain a polyimide solution SPI-A8. got it

(Synthesis Example 12)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 7.09 g (19.3 mmol) of DA-10, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 mmol) of DA-3. mol) was weighed, 60.5 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, 15.2 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.25 g (11.5 mmol) of CA-2 was added, 8.10 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1250 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain a polyimide powder (imidation rate: 75%), which was further dissolved in NMP to obtain a polyimide solution SPI-A9. got it

(Synthesis Example 13)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 7.40 g (19.3 mmol) of DA-11, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 mmol) of DA-3. mol) was weighed, 61.8 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, 15.2 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.30 g (11.7 mmol) of CA-2 was added, 8.20 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 980 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain polyimide powder (imidation rate: 81%), and further dissolved in NMP to obtain polyimide solution SPI-A10. got it

(Synthesis Example 14)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, add 9.17 g (19.3 mmol) of DA-12, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 mmol) of DA-3. mol) was weighed, 69.4 g of NMP was added, and it was dissolved by stirring while nitrogen was supplied. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, 14.8 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 1 hour. Furthermore, 2.34 g (12.0 mmol) of CA-2 was added, 8.30 g of NMP was further added, and the mixture was stirred at 23°C for 2 hours in a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1030 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain polyimide powder (imidation rate: 83%), and further dissolved in NMP to obtain polyimide solution SPI-A11. got it

(Synthesis Example 15)

In a 100 ml Erlenmeyer flask containing a stirrer, 30.0 g of the polyamic acid solution obtained in Synthesis Example 2 was aliquoted, 0.470 g of di-tert-butyl bicarbonate was added, and the mixture was reacted at 40° C. for 12 hours. Additionally, 20.0 g of NMP, 3.85 g of acetic anhydride, and 1.28 g of pyridine were added, stirred at room temperature for 30 minutes, and then reacted at 60°C for 4 hours. This reaction solution was poured into 220 g of methanol, and the obtained precipitate was separated by filtration. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain polyimide powder (imidation rate: 90%).

Furthermore, 3.50 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 25.6 g of NMP was added, and it was stirred and dissolved at 70°C for 24 hours to obtain polyimide solution SPI-A12.

(Examples 1 to 15) and (Comparative Examples 1 to 3)

For the solution obtained by mixing the polyamic acid solution obtained in Synthesis Examples 1 to 15 and the polyimide solution so as to have the ratio of polymer 1 and polymer 2 shown in the table below, NMP, GBL, BCS, and AD-1 were mixed. Examples 1 to 15 and comparisons were obtained by adding an NMP solution containing 1% by weight and an NMP solution containing 10% by weight of AD-2 while stirring so as to have the compositions shown in the table below, and stirring at room temperature for 2 hours. The liquid crystal aligning agents of Examples 1 to 3 were obtained.

Below, the manufacturing method of liquid crystal cell 1 for evaluating the pretilt angle and voltage retention, and liquid crystal cell 2 for evaluating liquid crystal orientation is shown.

[Manufacture of liquid crystal cell 1]

First, a substrate with electrodes attached was prepared. The substrate is a glass substrate with a size of 30 mm x 40 mm and a thickness of 1.1 mm. An ITO electrode with a film thickness of 35 nm is formed on the substrate, and the electrode has a stripe pattern of 40 mm in length and 10 mm in width.

Next, the liquid crystal aligning agent was filtered through a filter with a pore diameter of 1.0 μm, and then applied to the prepared substrate with electrodes by spin coating. After drying on an 80 degreeC hotplate for 2 minutes, baking was performed for 20 minutes in a 230 degreeC IR oven, the coating film with a film thickness of 100 nm was formed, and the board|substrate with a liquid crystal aligning film was obtained. This liquid crystal alignment film was rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 1000 rpm, movement speed: 20 mm/sec, indentation length: 0.4 mm), and then cleaned by ultrasonic irradiation in pure water for 1 minute. After removing the water droplets by air blowing, it was dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with a liquid crystal alignment film are prepared, and a spacer of 4 μm is spread on the liquid crystal alignment film surface of one sheet, then a sealant is printed from above, and the rubbing direction of the other substrate is reverse and the film surface is rubbed. After attaching them facing each other, the sealant was cured to produce an empty cell. Liquid crystal MLC-3019 (manufactured by Merck & Co., Ltd.) was injected into this empty cell by a reduced-pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. After that, the obtained liquid crystal cell was heated at 120°C for 1 hour, left to stand overnight at 23°C, and then used for each evaluation.

[Manufacture of liquid crystal cell 2]

A glass substrate attached to an electrode with a size of 30 mm × 35 mm and a thickness of 0.7 mm was prepared. On the substrate, an IZO electrode with a non-printed pattern constituting a counter electrode is formed as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed as the second layer by the CVD method is formed. The SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film as the third layer is disposed, forming two pixels, a first pixel and a second pixel. The size of each pixel is 10 mm vertically and approximately 5 mm horizontally. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-shaped shape, as shown in FIG. 3 of Japanese Patent Application Laid-Open No. 2014-77845, consisting of a plurality of "く" shaped electrode elements with a bent central portion arranged in an array. The width of each electrode element in the short direction is 3 μm, and the spacing between electrode elements is 6 μm. Since the pixel electrode forming each pixel is composed of a plurality of "く" shaped electrode elements arranged with a curved central portion, the shape of each pixel is not rectangular, but is curved in the central portion like the electrode element. , has a shape similar to the bold letter “く”. Each pixel is divided into upper and lower parts with the central curved part as a boundary, and has a first area above the curved part and a second area below the curved part.

When comparing the first region and the second region of each pixel, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, based on the rubbing direction of the liquid crystal alignment film, which will be described later, in the first area of the pixel, the electrode elements of the pixel electrode are formed to form an angle of +10° (clockwise), and in the second area of the pixel, the electrode elements of the pixel electrode are formed at an angle of +10° (clockwise). The electrode elements are formed to form an angle of -10° (clockwise). In addition, in the first region and the second region of each pixel, the directions of rotational motion (in-plane switching) of the liquid crystal within the substrate surface caused by application of voltage between the pixel electrode and the opposing electrode are opposite to each other. Consists of.

Next, after filtering the liquid crystal aligning agent through a filter with a hole diameter of 1.0 μm, an ITO film is formed on the back side as a counter substrate to the substrate with electrodes, and a glass substrate having a columnar spacer with a height of 4 μm. Spin coated each of the. Next, after drying on an 80 degreeC hot plate for 2 minutes, it baked at 230 degreeC for 20 minutes, and obtained the polyimide film with a film thickness of 60 nm on each board|substrate. This liquid crystal alignment film was rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 500 rpm, movement speed: 30 mm/sec, indentation length: 0.3 mm), and then cleaned by ultrasonic irradiation in pure water for 1 minute. After removing the water droplets by air blowing, it was dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film.

Using the two types of substrates to which the liquid crystal alignment film was attached, they were combined so that their rubbing directions were antiparallel, the surrounding area was sealed leaving a liquid crystal injection port, and an empty cell with a cell gap of 3.8 μm was manufactured. After vacuum injecting liquid crystal MLC-3019 (manufactured by Merck Co., Ltd.) into this empty cell at room temperature, the injection port was sealed to form a liquid crystal cell with antiparallel orientation. The obtained liquid crystal cell constituted an FFS mode liquid crystal display element. After that, the liquid crystal cell was heated at 120°C for 1 hour, left to stand at 23°C overnight, and then used for each evaluation described below.

<Pretilt angle>

The pretilt angle in the liquid crystal cell 1 was evaluated using an AxoScan Muller matrix polarimeter manufactured by OptoMatrix.

<Voltage maintenance rate>

A voltage of 1 V was applied to the liquid crystal cell 1 for 60 μsec at a temperature of 60°C, the voltage after 50 msec was measured, and the extent to which the voltage was maintained was evaluated as the voltage retention rate.

<Evaluation of liquid crystal orientation>

Using the liquid crystal cell 2, an alternating current voltage of 9 VPP was applied at a frequency of 30 Hz for 170 hours in a constant temperature environment of 60°C. After that, the space between the pixel electrode and the opposing electrode of the liquid crystal cell was short-circuited, and the liquid was left at room temperature for one day.

After being left overnight at 23°C, this liquid crystal cell is installed between two polarizers arranged so that their polarization axes are orthogonal, the backlight is turned on in a state where no voltage is applied, and the arrangement angle of the liquid crystal cell is adjusted so that the luminance of the transmitted light is the lowest. Adjusted. Then, the rotation angle when the liquid crystal cell is rotated from the angle at which the second area of the first pixel becomes darkest to the angle at which the first area becomes darkest is calculated as the angle Δθ1, and in the same way for the second pixel, the second area and The angle Δθ2 was calculated by comparing the first area. The average value of these Δθ1 and Δθ2 was set as the angle Δθ of the liquid crystal cell, and it was defined and evaluated that the smaller this value was, the better the liquid crystal orientation was.

For the liquid crystal display elements using each liquid crystal aligning agent of Examples 1 to 15 and Comparative Examples 1 to 3, the results of the pretilt angle, voltage retention, and angle Δθ of the liquid crystal cell performed as described above are shown in the table below. .

It can be seen that the liquid crystal display element using the liquid crystal aligning agent of the example of the present invention has a low pretilt angle, a high voltage retention rate, and good liquid crystal orientation.

By using the liquid crystal aligning agent of the present invention, a liquid crystal aligning film that satisfies the various characteristics required for the liquid crystal aligning film and provides a low pretilt angle of 1 degree or less can be obtained.

Claims (13)

It is a liquid crystal aligning agent containing polyimide, which is a reaction product of a tetracarboxylic acid dianhydride derivative component consisting of at least one type selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic dianhydride, and a diamine component, and a diamine component. This contains at least one type selected from the diamines of the following formula [A], the imidation rate of the polyimide is 70% or more, and the diamine of the formula [A] has the following formulas [A-1] to [A -6], and the liquid crystal aligning agent in which the said diamine component further contains the diamine which has the structure of following formula (6) in its structure.

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Moreover, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, if at least one of n1 and n2 is 0, Q is an oxygen atom.


In the above formula (6), D is a thermally desorbable group that desorbs at 150 to 230°C and is replaced by a hydrogen atom. According to claim 1,
A liquid crystal aligning agent whose imidation rate of the said polyimide is 75 % - 99 %. According to claim 1,
A liquid crystal aligning agent in which the diamine of the formula [A] is 40% to 80% of all diamine components. According to claim 1,
The liquid crystal aligning agent in which the diamine which has the structure of said Formula (6) is at least 1 type chosen from the following diamine.

In the formula, n is an integer from 1 to 12. According to claim 1,
The liquid crystal aligning agent in which aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride are represented by the following formula (4).

In the formula, X ₁ is a structure selected from the structures below.
According to claim 5,
A liquid crystal aligning agent in which said X ₁ is a structure selected from (X1-1-1), (X1-1-2), (X1-8), (X1-21), and (X1-24). According to claim 1,
A liquid crystal aligning agent in which the above-mentioned polyimide is obtained by reacting di-tert-butyl bicarbonate. According to claim 1,
Additionally, a liquid crystal aligning agent containing polyamic acid, which is a reaction product of a tetracarboxylic dianhydride derivative and diamine. According to claim 1,
The liquid crystal aligning agent is a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a crosslinkable compound having at least one substituent selected from the group consisting of a hydroxyl group, a hydroxyalkyl group and a lower alkoxyalkyl group, or a crosslinkable compound having a polymerizable unsaturated bond,
The said liquid crystal aligning agent whose content of the said crosslinkable compound is 0.1-150 mass parts with respect to 100 mass parts of all polymer components. A liquid crystal aligning film obtained from the liquid crystal aligning agent according to any one of claims 1 to 9. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10. delete delete